In the concept envisioned by biochemist Jeffrey Bland, Ph.D., in the early 1990s, physicians look at the underlying causes of disease using a systems-oriented approach — connecting threads that may be causing health issues instead of looking at an isolated set of symptoms.

Doctors look at the interactions between the environment and bodily systems that control a person's gastrointestinal, endocrine and immune systems. The goal is to try to get to the root of an individual's health problems instead of merely treating the symptoms.

Dr. Mark Hyman, head of the Institute for Functional Medicine at the Cleveland Clinic, explains the concept in more detail in the video below:

"Practitioners spend time with their patients," says Gabrielle Francis, a holistic physician in New York City. "The goal is to listen to their histories and look at the genetic, environmental and lifestyle factors that may be influencing their long-term health and chronic disease. Any testing that's done is then based not just on symptoms but the person as a whole."

For example, let's say 10 people go to the doctor complaining of chronic fatigue. The goal is to come up with different testing and treatment models for each individual, depending on the other variables at play.

"Each person has a different reason for feeling fatigued," Francis says. "For one, it may be adrenal, for another it's an autoimmune disease and another person might have an underlying infection. With functional medicine, you're looking at that person in the context of their whole life. Then you create a treatment plan."

It's an approach that appeals to a growing number of physicians.

"With functional medicine, everything is intuitive," says Deanna Minich, Ph.D., a certified functional medicine practitioner who teaches at the Institute for Functional Medicine, an education, training and research organization in Federal Way, Washington. "The goal is to help people make lifestyle changes so, for example, when a patient has cardiovascular disease, the idea is to align lifestyle changes with procedures, prescriptions and surgery."

And, even though it sometimes requires functioning outside of the insurance realm, it's gaining traction with doctors who want to practice medicine the way they intended.

"When practitioners come for functional medicine training, they usually remark that working with patients on the lifestyle factors affecting their health is the reason they went into medicine in the first place," Minich adds.

The main barrier to functional medicine? It takes time to get to the root of a patient's health problems.

"What we stress is taking a closer look at each and every patient, and that takes time," Minich says. "For example, if you notice that a patient has high blood pressure or high cholesterol, it's one thing to write a prescription for statins. In functional medicine, we open that lens and look at why the person has this — perhaps he or she has a metabolic issue or is consuming a sodium-rich diet."

The hope is that success — meaning healthier patients who are staying ahead of disease — will encourage more doctors and patients to embrace this whole body approach.

"Unfortunately, most physicians aren't able to scratch the surface," Minich says. "Not when they have just seven to 10 minutes with every patient."